Take a Peek Inside the 747-8 Test Plane

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Take a Peek Inside the 747-8 Test Plane

The second production 747-8 undergoing finally assembly

EVERETT, Washington – Well into the first flight of Boeing's new 747-8, co-pilot Tom Imrich brought up the fuel page on a display in the cockpit. Chief pilot Mark Feuerstein did a double take when he saw it. The biggest airliner Boeing has ever built left Paine Field carrying 130,000 pounds of jet fuel. But the plane, which Boeing is hailing for its efficiency, was burning less fuel than expected.

"You're generally familiar with the odd burns – off nominal, and you know what they are," Feuerstein said, explaining the unusual flying conditions of a first flight. "I said, 'This is amazing.'"

Feuerstein made some quick calculations and realized they would have much more fuel remaining than expected when they landed after an inaugural flight slated to last four hours.

"We looked at the fuel flows at one point, and the telemetry room at Boeing Field wanted to know what time we would land," he said after Monday's flight. "I asked them if 10 o'clock tonight would be okay."

They said no.

The flight touched down at 4:18 p.m. local time after 219 minutes in the air. Feuerstein's comments about the fuel burn were a great thing to say for a company marketing its new plane as an efficient alternative to the competition. The experienced pilots were quick to note it will require a closer look at the data before anyone can confirm an actual fuel burn number. But at a glance, the efficient wing design and engines appear to be holding up their end of the deal.

At takeoff, the 747-8 weighed about 630,000 pounds, relatively light for a 747 flight. Feuerstein said they used 20 degrees of flaps and rotated at 152 knots. The plane lifted off the ground at around the 4,000 foot marker. The landing was made with 25 degrees of flaps and at 151 knots. Feuerstein says these speeds were six to seven knots faster that what the airplane will do once in service.

"That's just obviously to cover the uncertainties that might be out there," Feuerstein said.

Feuerstein said they touched all the systems during the flight, including shutting down the engines. When asked which engine was shut down, he replied, "All of them." Laughing, he quickly clarified, "But we did it one at a time!"

While the pilots were busy flying, we stayed busy having a look at the next 747-8s as they were being prepared for their first flights.

The Boeing factory is the largest building in the world by volume. It's the same building where the first 747 was built more than 40 years ago. Currently Boeing's biggest aircraft, the 747-8, along with the 767 (assuming it continues), 777 and 787 Dreamliner are all built in the factory at the north end of Paine Field here in Everett.

The building is huge. It covers 4.3 million square feet and contains 472 million cubic feet of space. Amazingly, the building has no heating or air conditioning. It is heated by more than 1 million light bulbs, numerous computers, people and other equipment. If it gets too hot, employees crack open the massive 82-by-300-foot doors to let in a little fresh air.

The place is so big it even had its own weather for a bit. When the building was first built, clouds formed near the ceiling. Improved air circulation fixed that. More than 30,000 people work at the factory in three shifts. There are 1,300 bicycles for them to ride since it is more than half a mile from one end of an assembly line to the other.

Inside the building, a few assembly lines down from where the 787s are being built, the first production models of the 747-8 are nearing completion. There are three parked outside, including the one that flew Monday. Numbers four, five and six are nearly done and will be the first nontest aircraft flown.

15,000 pound weights hang from the engine pylons on the first production aircraft

Because the test aircraft have to be refit for customer use before they are delivered, the aircraft now in the factory will be the first received by customers. The first two are going to launch customer Cargolux, while the third will be delivered to Guggenheim Leasing Partners.

After a look inside the factory, it was time to have a look inside the second test aircraft. While the first plane flown, airframe No. RC501, will continue initial air-worthiness testing, RC521 (different customer, different number series) will be used for systems testing including autolanding and propulsion systems.

The 747-8 is immense. It looks almost identical to the current model, the 747-400. But behind the characteristic hump, the stretched fuselage now measures more than 250 feet long. The wingspan is 224 feet 7 inches. The plane can carry more than 550,000 pounds of cargo at speeds of more than 560 mph. Fully loaded, it tips the scales at 975,000 pounds.

All that mass will be carried by a completely new wing and engines. Many of the internal systems are new as well, including the flight control computer. All that new technology allows the 747-8 to carry more passengers or cargo further for less money.

The interior is equally vast. The first planes slated for production are cargo planes, so there are no luggage bins or bulkheads to divide the open space. You could put on a small circus inside a 747-8.

Inside the cavernous 747-8 test aircraft

The interiors are all business for flight test. In the front of the airplane, there are 16 water ballast tanks with another 16 in the aft end. A single ballast tank also sits closer to the middle and it looks like there's a spot for one more across the aisle.

Water ballast tanks used to control center of gravity during test flights

These tanks are filled with water and engineers can transfer water between the tanks during flight to shift the weight of simulated cargo or passengers. The center of gravity, or CG as pilots call it, is important to the flight characteristics of any airplane. During flight test, Boeing must ensure the plane is safe and efficient at full forward and full aft CG as well as any combination between the two.

Several engineering stations dominate the middle of RC521. The racks of computers are for data collection, and most have terminals where engineers will sit during test flights to analyze data as various maneuvers are performed and systems checked. Feuerstein took us through some of the moves in a 747-8 simulator last month.

Flight test engineer station inside 747-8

Feuerstein told us there isn't anything that makes his heart jump while he's flying test points, but the engineers in the windowless cargo hold have to endure various maneuvers while keeping their eyes glued to a screen. That sounds like a reason for eating something that may taste as good coming up as it did going down. Depending on the test flight, 10 to 22 engineers are on board.

Aft ballast tanks and static cone cable reel

One of the more unusual devices inside the test aircraft was a giant wheel at the very end of the plane. It is used to reel in and reel out the small cone (shown below) that trails behind the airplane to provide an accurate static pressure reading during flight testing.

Trailing cone used for static air pressure during test flights

Eventually the inside tour came to an end and it was time to get back to the runway to watch RC501 touch down after three hours and 39 minutes in the air. There are some 1,600 hours of flight tests still to do. Boeing will install more equipment on the aircraft and flight testing will continue at Moses Lake in central Washington. After that, the aircraft will be moved to Palmdale, California, where the remaining tests will be completed.

Boeing says Cargolux will receive its first 747-8 before the end of the year.